Roberto is probably a bit small and past his best by 1989. I never rated Nunn's ability to stay out of trouble, but how much offence would Duran be able to mount, probably 10 years past his best, and at such a size and reach disadvantage? Nunn, but again, I can't see it being a great fight.
Nunn by comfortable decision in a dreadful fight where he guts butted and heeled by an irritated Duran several times